Current computing systems rely upon anti-virus (AV) software and message filters to allow the secure transfer of files from un-trusted computing systems into trusted computing systems. An un-trusted computing system may consist of, for example, a single unclassified computer system, a network of unclassified computer systems, or a publicly accessible corporate computer network. A trusted computing system may consist of, for instance, a classified computer system or network, or a private corporate network. Un-trusted computing systems and trusted computing systems are referred to generally as un-trusted and trusted computer systems.
Current systems for transferring files from an un-trusted to a trusted computer system rely on anti-virus (AV) software to eliminate malware hidden within uploaded files. This approach, however, is not without certain drawbacks. First, the AV software's malware definitions must be continuously updated to ensure that the file transfer is conducted with up-to-date virus definitions. Second, the malware definitions may not include signatures for malware not previously encountered and so cannot prevent zero-day attacks.